The discusser observes that the most undersirable aspect of "new design procedure" is the use of the NSP concept in order to reduce the number of required tests. In the proposed method, the undrained shear strength is determined by means of a limited number of more sophisticated tests. This information is not used directly but first normalized in terms of OCR. This intermediate step which involves normalization and use of oedometer tests to define the in-site OCR profile, has very serious shortcomings. All natural clays possess a structure that is destroyed, and therefore, in-situ undrained shear strength behavior is altered whenever the clay is consolidated in stresses in excess of the critical pressure. The observation is also made that the determination of the OCR from oedometer tests involves at least as much uncertainity as the measurement of the undrained strength itself. The new design procedure introduces an additional uncertainity into the evaluation of undrained shear strength. Attention is drawn to the implication of Bjerrum's correction factors for FV data. Interesting questions are asked with regard to the relationships and the effects of strain rate and anisotropy, and the relation (if any) between the shear strength and plasticity index.

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  • Accession Number: 00096255
  • Record Type: Publication
  • Report/Paper Numbers: Discussion
  • Files: TRIS
  • Created Date: Jul 15 1975 12:00AM